human visual system - computer science and...
TRANSCRIPT
CSE252a, Fall 2011 Computer Vision I
Human Visual System
Computer Vision I CSE 252 Lecture 2
CSE252a, Fall 2011 Computer Vision I
Announcement Assignment 0: “Getting started with Matlab”
is posted to the web page and due next Tuesday.
CSE252a, Fall 2011 Computer Vision I
Kepler
Kepler, 1604
Eye as an optical instrument
Image is inverted on retina
First such experiment by Scheiner, 1625
CSE252a, Fall 2011 Computer Vision I
Ways to study human vision 1. Physiological 2. Phenomenological/Psychophysical 3. Cellular recordings 4. Functional MRI 5. Computational modeling
CSE252a, Fall 2011 Computer Vision I
Physiological level
CSE252a, Fall 2011 Computer Vision I
What does this do?
Can we readily understand whole from understanding pieces?
CSE252a, Fall 2011 Computer Vision I
Ways to study human vision 1. Physiologically 2. Phenomenological/Psychophysical 3. Cellular recordings 4. Functional MRI 5. Computational modelling
CSE252a, Fall 2011 Computer Vision I
Psychophysical Testing of Subjects
CSE252a, Fall 2011 Computer Vision I
Example: Show gratings w/ different spatial frequencies
CSE252a, Fall 2011 Computer Vision I
Gradients/Motion
Look Here
CSE252a, Fall 2011 Computer Vision I
Perceptual Organization
Occlusion provides a different organization
CSE252a, Fall 2011 Computer Vision I
Perceptual Organization
CSE252a, Fall 2011 Computer Vision I
Ways to study human vision 1. Physiologically 2. Phenomenological/Psychophysical 3. Cellular recordings 4. Functional MRI 5. Computational modeling
CSE252a, Fall 2011 Computer Vision I
Single Cell Recordings
CSE252a, Fall 2011 Computer Vision I
fMRI
Activation in the right fusiform gyrus. [ Tarr, Cheng 2003]
CSE252a, Fall 2011 Computer Vision I
Ways to study human vision 1. Physiologically 2. Phenomenological/Psychophysical 3. Cellular recordings 4. Functional MRI 5. Computational modeling
CSE252a, Fall 2011 Computer Vision I
Computational Modeling
What is being computed and why?
CSE252a, Fall 2011 Computer Vision I
Structure of the eye
CSE252a, Fall 2011 Computer Vision I 1 lux = 1 lumin/m2
CSE252a, Fall 2011 Computer Vision I
Rods and cones
Cones
CSE252a, Fall 2011 Computer Vision I
Rods & Cones
CSE252a, Fall 2011 Computer Vision I
Three types of cones: R,G,B
There are three types of cones S: Short wave lengths (Blue) M: Mid wave lengths (Green) L: Long wave lengths (Red)
• Three attributes to a color • Three numbers to describe a color
Response of k’th cone =
CSE252a, Fall 2011 Computer Vision I
Distribution of Rods & Cones
CSE252a, Fall 2011 Computer Vision I
Retina edge on
CSE252a, Fall 2011 Computer Vision I
Retinal Neuron
CSE252a, Fall 2011 Computer Vision I
Other Eyes
CSE252a, Fall 2011 Computer Vision I
Trilobite Visual System • Most ancient known visual system. • Compound eye with single crystal for each
lens. Electron Micrograph of Holochroal eye
Good trilobite eye info at: http://www.aloha.net/~smgon/eyes.htm
CSE252a, Fall 2011 Computer Vision I
Scallop eyes • Hundreds of primitives eyes, mirror in back • Changes in light and motion and very rough images are
registered on the retinas of the mollusk. • Nice material at: http://soma.npa.uiuc.edu/courses/bio303/Ch11b.html
CSE252a, Fall 2011 Computer Vision I
Stomatopod eyes • Dumb bell shaped, compound eyes • Stereo vision with just one eye; • Each eye is up on a stalk, with a wide range of motion; • Stomatopods have up to 16 visual pigments stomatopods
can also see ultra-violet and infra-red light, and some can even see polarized light.
• See http://www.ucmp.berkeley.edu/aquarius/
Larva Mantis Shrimp Adult Mantis Shrimp
CSE252a, Fall 2011 Computer Vision I
Visual Pathways
CSE252a, Fall 2011 Computer Vision I
Single Cell Recordings
CSE252a, Fall 2011 Computer Vision I
What: Recognition, Object representation
Where: Location & Motion, control
CSE252a, Fall 2011 Computer Vision I
CUES
CSE252a, Fall 2011 Computer Vision I
Fixate at center What color are the dots
CSE252a, Fall 2011 Computer Vision I
Shading Cues
CSE252a, Fall 2011 Computer Vision I
Subjective Contours Kanizsa’s Triangle
CSE252a, Fall 2011 Computer Vision I
Which square is darker?
CSE252a, Fall 2011 Computer Vision I
Which square is darker?
CSE252a, Fall 2011 Computer Vision I
Global vs. Local information: Fraser’s Spiral
CSE252a, Fall 2011 Computer Vision I
CSE252a, Fall 2011 Computer Vision I
CSE252a, Fall 2011 Computer Vision I
Context
Who is taller? Who is taller?
CSE252a, Fall 2011 Computer Vision I
Context: Whose faces do you see?
CSE252a, Fall 2011 Computer Vision I
A picture of a man
CSE252a, Fall 2011 Computer Vision I
In this shot, what is his facial exprssion?
CSE252a, Fall 2011 Computer Vision I
In this shot, what is his facial exprssion?
Thatcher illusion
CSE252a, Fall 2011 Computer Vision I
Hidden Human Face